<template>
    <div>
        <h1>{{sum}}</h1>
        <select v-model.number="n">
            <option value="1">1</option>
            <option value="2">2</option>
            <option value="3">3</option>
        </select>
        <button @click="increment">+</button>
        <button @click="decrement">-</button>
        <button @click="incrementOdd">当前求和为奇数再加</button>
        <button @click="incrementwait">等一等再加</button>
    </div>
</template>

<script>
    export default {
        name:'Count' ,
        data() {
            return {
                n:1,  //用户选择的数字
                sum:0  //当前的和
            }
        },
        methods: {
            increment(){
                this.sum += this.n
            },
            decrement(){
                this.sum -= this.n
            },
            incrementOdd(){
                if(this.sum%2){
                    this.sum += this.n
                }
            },
            incrementwait(){
                setTimeout(()=>{
                    this.sum += this.n
                },200)

            }
        },
}  
</script>

<style lang="css">
    button{
        margin-left: 5px;
    }
    
</style>
